my app is showing Sales Orders and Sales Lines. On the SalesLines Gallery i can press a button which switches me on the form, where i can edit the selected entry. But when i submit the changes, it says: Invalid Mashup Expression using supplied values. inner exception: The value is not updatable.
before i tried Dynamics NAV as datasource, i have tried Excel and it worked with it.
Could it be that powerapps can only read data using a Dynamics NAV Odata Source?